Alfalfa is a crop which has not been, up till now, utilized to its full extent and is often generally used simply as a feed material for animals. However alfalfa has significant potential in that it has a high nutrition content and if processed effectively can be used for a number of different end products.
It has been proposed previously to pass the alfalfa through a press which extracts juice which can be used separately and in addition provides a product which is compressed and of reduced moisture content for more effective drying. One example of press of this type is shown in U.S. Pat. No. 4,125,070 (Besnard) and this includes a main press roller with a plurality of subsidiary rollers arranged at angularly spaced position around the main roller and each defining a nip with the main press roller for compressing the material and extracting juice. This press has however been of reduced effectiveness due to an inability to properly feed the material from a feed system into the nips.
The above press has been proposed for use with a previous dryer arrangement in which the compressed alfalfa is fed into a rotating drum. One example of a dryer of this type is shown in a brochure by M-E-C Company. The drum is horizontal with an inlet at one end and an outlet at an opposed end. A fan draws air through the drum so that the compressed crop material is deposited into the air stream passing through the drum at the inlet end of the drum and is carried through the drum to a separation cyclone at the outlet end of the drum. A combustion chamber is directly attached to the inlet end of the drum so that combustion products and heat are injected into the interior of the drum and are carried through the drum with the air stream and the crop material to be dried.
This proposed arrangement of the press and the drying apparatus has achieved some success. However the drawing apparatus also has some disadvantage in that the combustion products are directly carried into and mixed with the crop materials leading to an accumulation of benzopyrene and other combustion products in the crop materials which can be highly hazardous to the subsequent use or consumption of the product.